the growth of the industry also symbolizes the growth of the city. archaeologists believe population size along with density has a critical effect on the economy of a city. once you get 90,000 people in one place, or 60,000 people in one place, then it has a self-generating kind of impact on its structure. all those people living here means that it's going to stimulate economic specialization. economic specialization itself then is going to change the character of the city. keach: was increased specialization actually changing life in teotihuacan ? warren barbour began to think the tiny faces would yield an answer. barbour: during my dissertation research, i occasionally would run across figurines that had fingerprints, and they sort of added a humanity to my work, and i started looking for them, and they sort of brought me closer to the manufacturer of the print. i started wondering who he was, and i figured i would never be able to find that. and i started wondering whether or not i could find something else out about them. keach: barbour's curiosi